oneelectronreduced

Oneelectronreduced refers to a chemical species that has gained one electron in a reduction process relative to its oxidized form. In redox chemistry, such species are typically radical species, most commonly radical anions when the starting substrate is neutral. The term is used across organic molecules, inorganic complexes, and biological redox systems to describe the one-electron reduced state.

Typical examples of oneelectronreduced species include semiquinones, which are the one-electron reduced forms of quinones, and radical anions of various organic and inorganic substrates. The location of the unpaired electron in a oneelectronreduced species—whether on a ligand, a metal center, or within an extended π-system—depends on the electronic structure, conjugation, and solvent environment of the system.

Properties of oneelectronreduced species are frequently characterized by paramagnetism, making them amenable to detection by electron paramagnetic resonance (EPR). They often exhibit distinct optical absorption features in the visible or near-infrared regions and can be short-lived in air unless stabilizing factors such as resonance or steric protection are present. In solution, their lifetimes are influenced by interactions with solvent, oxygen, and other redox partners.

Applications and relevance of oneelectronreduced species span electrochemical reduction, photoredox catalysis, and energy storage technologies, including redox flow and dye-sensitized systems. They also play significant roles in biological electron transfer processes, where semiquinone and related radicals participate in mitochondrial and photosynthetic pathways. See also radical anion, semiquinone, electron transfer, and redox chemistry for related concepts.